CARRIER BEARING OR PINION BEARING PROBLEM

I had an independent mechanic drive my car due to a humming noise coming from the rear of car. He said it sounds like either carrier or pinion bearing and to take it to the Jeep dealership. Car is there now. I asked service manager if it were one of the 2 things above, would it be covered under 70,000 Power Train warranty and he said no. I pulled warranty paperwork and it says: transfer case and all internal parts, transfer case control module and shift mode motor assembly, axle housing and all internal parts, axle shafts, axle shaft bearings; drive shaft assemblies (front & rear), drive shaft center bearings, universal joints & yokes, disconnect housing assembly, seals and gaskets for listed components only.I am not a car person. Do any of the above parts fall under a Carrier or Pinion bearing? I don't trust dealership service and want to be sure I am not being ripped off! Thanks!